manager.java

有关j2me的很好的例子可以研究一下

     * Appends a names of all the MIDlets in a suite to a Form, one per line.
     *
     * @param midletSuite suite of MIDlets
     * @param form form to append to
     */
    private void appendMIDletsToForm(MIDletSuite midletSuite, Form form) {
        int numberOfMidlets;
        MIDletInfo midletInfo;

        numberOfMidlets = midletSuite.getNumberOfMIDlets();
        for (int i = 1; i <= numberOfMidlets; i++) {
            midletInfo = new MIDletInfo(
                             midletSuite.getProperty("MIDlet-" + i));
            form.append(midletInfo.name);
            form.append("\n");
        }
    }

    /**
     * Read the set of MIDlet names, icons and classes
     * Fill in the list.
     */
    private void setupList() {
        if (mlist == null) {
            mlist = new List(Resource.getString("Main Screen"), 
                             Choice.IMPLICIT);

            // Add each midlet
            for (int i = 0; i < mcount; i++) {
                mlist.append(" " + minfo[i].displayName, minfo[i].icon);
            }
        }
    }
        
    /**
     * Read in and create a MIDletInfo for each MIDlet suite.
     */
    private void readMIDletSuiteInfo() {
        String[] suiteNames;
        MIDletSuite midletSuite;
        int i;
        int numberOfMidlets;
        String nth;
        String attr;
        byte[] rawPng;

        suiteNames = installer.list();

        for (i = 0; i < suiteNames.length; i++) {
            try {
                midletSuite = installer.getMIDletSuite(suiteNames[i]);

                numberOfMidlets = midletSuite.getNumberOfMIDlets();

                if (numberOfMidlets > 1) {
                    addMIDletSuite(new MIDletSuiteInfo(suiteNames[i],
                                                       midletSuite));
                }

                for (int j = 1; j <= numberOfMidlets; j++) {
                    nth = "MIDlet-"+ j;
                    attr = midletSuite.getProperty(nth);
                    if (attr == null || attr.length() == 0) {
                        break;
                    }
                    
                    addMIDletSuite(new MIDletSuiteInfo(suiteNames[i],
                                                       midletSuite, attr));
                }

                if (numberOfMidlets == 1) {
                    minfo[mcount - 1].singleMidlet = true;
                    minfo[mcount - 1].icon = getSingleSuiteIcon();
                }
            } catch (Exception e) {
                // move on to the next suite
            }
        }
    }

    /**
     * Add a MIDlet suite to the list.
     * @param info MIDlet suite information to add to MIDlet
     */
    private void addMIDletSuite(MIDletSuiteInfo info) {
        if (mcount >= minfo.length) {
            MIDletSuiteInfo[] n = new MIDletSuiteInfo[mcount+4];
            System.arraycopy(minfo, 0, n, 0, mcount);
            minfo = n;
        }

        minfo[mcount++] = info;
    }

    /**
     * Simple attribute storage for MIDlet suites
     */
    private class MIDletSuiteInfo {
        /** Midlet suite interface for displaying its info. */
        MIDletSuite midletSuite;
        /** Storage name of the MIDlet suite. */
        String storageName;
        /** Display name of the MIDlet suite. */
        String displayName;
        /** Name of the MIDlet to run. */
        String midletToRun;
        /** Icon for this suite. */
        Image icon;
        /** Icon name for the first midlet. */
        String iconName;
        /** Is this single MIDlet MIDlet suite. */
        boolean singleMidlet = false;

        /**
         * Constructs a MIDletSuiteInfo object for a suite
         *
         * @param theStorageName name the installer has for this suite
         * @param theMidletSuite MIDletSuite object for this suite
         */
        MIDletSuiteInfo(String theStorageName, MIDletSuite theMidletSuite) {
            midletSuite = theMidletSuite;
            displayName = midletSuite.getProperty(Installer.SUITE_NAME_PROP);
            if (displayName == null) {
                displayName = theStorageName;
            }

            icon = getSuiteIcon();
            storageName = theStorageName;
        }

        /**
         * Constructs a MIDletSuiteInfo object for a MIDlet of a suite
         *
         * @param theStorageName name the installer has for this suite
         * @param theMidletSuite MIDletSuite object for this suite
         * @param attr an MIDlet-<n> value for the MIDlet
         */
        MIDletSuiteInfo(String theStorageName, MIDletSuite theMidletSuite,
                        String attr) {
            MIDletInfo midletInfo = new MIDletInfo(attr);

            midletSuite = theMidletSuite;

            displayName = midletInfo.name;
            icon = getEmptyIcon();

            iconName = midletInfo.icon;
            storageName = theStorageName;
        }
    }

    /** A class to install a suite in a background thread. */
    private class BackgroundInstaller implements Runnable, InstallListener {
        /** Parent manager. */
        private Manager parent;
        /** JAD URL to install from. */
        private String jadUrl;
        /** Name of MIDlet suite. */
        private String name;
        /**
         * Message for the user after the current install completes
         * successfully.
         */
        private String successMessage;
        /** Flag to overwrite the current suite. */
        private boolean overwrite;
        /** State of the install. */
        InstallState installState;
        /** Signals that the user wants the install to continue. */
        boolean continueInstall;

        /**
         * Construct a BackgroundInstaller.
         *
         * @param theParent parent Mangager of this object
         * @param theJadUrl where to get the JAD.
         * @param theName name of the MIDlet suite
         * @param theSuccessMessage message to display to user upon success
         * @param overwriteFlag if true the current suite should be
         *                      overwritten without asking the user.
         */
        private BackgroundInstaller(Manager theParent, String theJadUrl,
                String theName, String theSuccessMessage,
                boolean overwriteFlag) {
            parent = theParent;
            jadUrl = theJadUrl;
            name = theName;
            successMessage = theSuccessMessage;
            overwrite = overwriteFlag;
        }

        /**
         * Run the installer.
         */
        public void run() {
            try {
                parent.installer.install(jadUrl, overwrite, this);
                parent.displaySuccessMessage(successMessage);

                /*
                 * We need to prevent "flashing" on fast development
                 * platforms.
                 */
                while ((System.currentTimeMillis() -
                        parent.lastDisplayChange) < parent.ALERT_TIMEOUT);

                parent.destroyApp(false);
                parent.notifyDestroyed();
                return;
            } catch (Throwable ex) {
                String msg;

                if (parent.installer != null &&
                        parent.installer.wasStopped()) {

                    /*
                     * We need to prevent "flashing" on fast development
                     * platforms.
                     */
                    while ((System.currentTimeMillis() -
                        parent.lastDisplayChange) < parent.ALERT_TIMEOUT);

                    parent.display.setCurrent(parent.mlist);
                    return;
                }

                if (ex instanceof InvalidJadException) {
                    msg = translateJadException((InvalidJadException)ex,
                                                name, jadUrl);
                } else if (ex instanceof IOException) {
                    msg = Resource.getString(
                          "The connection dropped and the installation " +
                          "did not complete. Please try installing again.");
                } else {
                    msg = ex.getMessage();
                }
            
                Alert a = new Alert(Resource.getString("Install Error"), 
                                    msg, null, AlertType.ERROR);
                a.setTimeout(Alert.FOREVER);
                parent.display.setCurrent(a, parent.mlist);
            }
        }

        /**
         * Called with the current state of the install so the user can be
         * asked to override the warning. Calls the parent to display the
         * warning to the user and then waits on the state object for
         * user's response.
         *
         * @param state current state of the install.
         *
         * @return true if the user wants to continue,
         *         false to stop the install
         */
        public boolean warnUser(InstallState state) {
            boolean temp;

            installState = state;

            InvalidJadException e = installState.getLastException();

            if (e.getReason() == InvalidJadException.UNAUTHORIZED) {
                parent.getUsernameAndPassword();
            } else {
                parent.warnUser(name, jadUrl, e);
            }

            synchronized (installState) {
                try {
                    installState.wait();
                } catch (InterruptedException ie) {
                    // ignore
                }
            }

            installState = null;
            temp = continueInstall;
            continueInstall = false;
            return temp;
        }

        /**
         * Called with the current status of the install.
         * Changes the status alert box text based on the status.
         *
         * @param status current status of the install.
         */
        public void updateStatus(int status) {
            parent.updateStatus(status);
        }
    }

    /** A class to get the install list in a background thread. */
    private class BackgroundInstallListGetter implements Runnable {
        /** Parent manager. */
        private Manager parent;
        /** URL of the list. */
        private String url;

        /**
         * Construct a BackgroundInstallListGetter.
         *
         * @param theParent parent Mangager of this object
         * @param theUrl where to get the list of suites to install.
         */
        private BackgroundInstallListGetter(Manager theParent,
                                            String theUrl) {
            parent = theParent;
            url = theUrl;
        }

        /**
         * Get the list of suites for the user to install.
         * The suites that are listed
         * are the links on a web page that end with .jad.
         */
        public void run() {
            StreamConnection conn = null;
            InputStreamReader in = null;
            String errorMessage;
            long startTime;

            startTime = System.currentTimeMillis();

            try {
                conn = (StreamConnection)Connector.open(url, Connector.READ);
                in = new InputStreamReader(conn.openInputStream());
                try {
                    displayConnectingForm("Getting Install List", "", url);
                    parent.installList =
                        SuiteDownloadInfo.getDownloadInfoFromPage(in);
                    
                    if (parent.installList.size() > 0) {
                        parent.installListBox = new List(Resource.getString(
                                                "Select one to install:"),
                                                Choice.IMPLICIT);

                        // Add each suite
                        for (int i = 0; i < parent.installList.size(); i++) {
                            SuiteDownloadInfo suite =
                                (SuiteDownloadInfo)installList.elementAt(i);
                            parent.installListBox.append(suite.label,
                                                         (Image)null);
                        }

                        parent.installListBox.addCommand(backCmd);
                        parent.installListBox.addCommand(installCmd);
                        parent.installListBox.setCommandListener(parent);

                        /*
                         * We need to prevent "flashing" on fast development
                         * platforms. 
                         */
                        while (System.currentTimeMillis() - startTime < 
                            parent.ALERT_TIMEOUT);

                        display.setCurrent(parent.installListBox);
                        return;
                    }

                    errorMessage = Resource.getString(
                        "No MIDlet Suites found. " +
                        "Check the URL to make sure it is correct.");
                } catch (Exception ex) {
                    errorMessage = ex.getMessage();
                }
            } catch (Exception ex) {
                errorMessage = Resource.getString(
                    "The connection failed. Please check the website " +
                    "URL and try again.");
            } finally {
                try {
                    conn.close();
                    in.close();
                } catch (Exception e) {
                    // ignore
                }
            }

            Alert a = new Alert(Resource.getString("Error"), 
                                errorMessage, null, AlertType.ERROR);
            a.setTimeout(Alert.FOREVER);
            display.setCurrent(a, parent.mlist);
        }
    }
}